3D-Printed Fluidic Devices and Incorporated Graphite Electrodes for Electrochemical Immunoassay of Biomarker Proteins

3D printing has gained substantial interest as an adaptable and low-cost technology for rapid prototyping and production of research tools owing to its fast design-to-object workflow (Fig. 1), ease of operation, and ability to fabricate relatively complex and intricate structures directly from computer-aided design (CAD) representations. Due to the advantages 3D printing offers over other more time-consuming and labor-intensive fabrication methods like photolithography, 3D printing has been especially helpful in the development and production of flow cells and other fluidic devices. 3D printing allows for complex channel geometries, and the complete structure, including ports for connecting commercially available tubing, may be prepared from a single CAD file. As a result of these conveniences, 3D-printed fluidic devices have recently emerged as effective candidates for research in sensing applications. In these studies, we demonstrate electrochemical immunoassays for the biomarker protein S100B, which has been related to conditions like skin cancer and brain injuries, based on 3D-printed flow-cells with modularly integrated electrodes. The fluidic devices in these studies are prepared from photocurable resin and feature channel dimensions of ~400 µm. The device design includes ports for interfacing the channel with commercial fittings and tubing for fluid delivery as well as an access point for the antibody-modified electrode. Sensing is accomplished through a sandwich-type electrochemical immunoassay strategy, leading to sensitive detection of S100B.